PROJECT SUMMARY/ABSTRACT While evidence-based behavioral treatments for adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD) are well-established, these interventions most often fail to generalize across settings and are associated with intervention effects that dissipate over time. The current proposal takes a theory-driven, empirical approach for optimizing existing behavioral treatment by targeting adolescents? skills utilization and engaging other modifiable factors associated with trajectories of ADHD-related impairment including reward sensitivity, motivation, executive functioning, and social support. Mobile technologies offer transformative opportunities for engaging these targets and overcoming the notorious challenges impeding treatment adherence for adolescents with ADHD. This mentored K23 award will support the candidate in developing an independent research career investigating innovative approaches for optimizing treatment response for youth with ADHD. This K23 is designed to provide the necessary training to become an expert in leveraging technology-enhanced resources to target behavioral skill utilization in order to enhance treatment response and promote sustained improvement. This award will provide the candidate with advanced training in: (1) interactive health technologies; (2) adherence promotion; (3) methods and statistical approaches for ecological valid, real time assessment and adaptive intervention designs; and (4) mechanism-based intervention refinement and evaluation; and (5) grant writing skills and research dissemination. Through the University of California, San Francisco (USCF) Laboratory for Hyperactivity, Attention, and Learning Problems (HALP) and the UCSF?s Clinical and Translational Science Institute (CTSI) Award, the candidate is uniquely equipped with resources to achieve her training objectives and complete this research. The mentorship team includes senior level investigators with active federally-funded research, experience mentoring early-career investigators, and expertise in: implementing persuasive technology for adherence and behavior change (Lyles), user-centered design, development, and evaluation with adolescents (Ozer), human-computer interaction and gamification (Gazzaley), ecological skills assessment (Lindhiem), adaptive intervention designs with digital tools (Murphy), and mechanisms underlying interventions (Pfiffner; HALP Director, primary mentor). Applying this training, the proposed research will use an iterative stakeholder-centered design to develop, refine, and preliminarily test a scalable digital health tool, applied as an adjunct to behavioral treatment for adolescents with ADHD (ages 11- 14). Following usability testing to guide refinements, a small pilot RCT (N=60) will examine target engagement and validation (skills utilization) for promoting enhanced and evaluate the feasibility of this novel tool when integrated with treatment delivery. The training, mentorship, and research supported by this K23 will facilitate the candidate in designing the next phase of this research, a large-scale adaptive intervention trial (R01) that delivers personalized strategies to optimize treatment engagement and skills utilization in real time.